Spot Forecast
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
954
FNUS75 KRIW 032025
FWSRIW
Spot Forecast for Big Sandy Piles...USFS
National Weather Service Riverton WY
125 PM MST Wed Dec 3 2025
Forecast is based on ignition time of 0800 MST on December 04.
If conditions become unrepresentative, contact the National Weather
Service
.DISCUSSION...
Correction...Northwest winds prevail Thursday, with speeds 10 to 15 mph
and gusts around 20 mph in the morning, increasing after 1200L to around
25 mph. Gusty winds around 20 mph continue through Thursday night. A
mostly clear sky Thursday morning, but increasing clouds through the
afternoon, especially starting about 1500L, ahead of the next
weather system. Thursday night, the chance for any light snow
remains low (10-15 percent). Smoke dispersal is poor for most of
Thursday, with a small period of fair conditions possible between
1300 and 1600L.
Looking ahead, snow chances increase late Friday morning, with
chances around 80 percent by sunset. Heaviest snow occurs Friday
night, with lighter snow lingering into Saturday.
...Thunderstorms imply strong gusty and erratic winds...
.THURSDAY...
Sky/weather.........Mostly sunny (30-40 percent) then becoming
mostly cloudy (65-75 percent) after 1400.
CWR.................0 percent.
Chance of pcpn......10 percent.
Max temperature.....Around 22.
Min humidity........63-67 percent.
Wind (20 ft)........Northwest winds 10 to 15 mph with gusts to
around 25 mph, especially after 1200.
Ridgetop wind.......Northwest 15 to 20 mph.
Mixing height.......2000 ft AGL.
Transport winds.....Northwest 15 to 25 mph.
Smoke dispersal.....Poor until 1300, then fair in the afternoon until
1700, then poor.
TIME (MST) 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........30 25 20 15 20 20 25 40 55 70
Weather cov.....
Weather type....
Tstm cov........
CWR.............0 0 0 0 0 0 0 0 0 0
Chc of pcpn (%).0 0 0 0 0 0 0 0 10 10
Temp............10 14 17 21 21 21 22 20 19 17
RH..............82 76 71 65 66 67 68 70 72 74
20 FT wind dir..NW NW NW NW W W NW NW NW NW
20 FT wind spd..10 11 12 13 13 14 14 14 13 11
20 FT wind gust.16 17 18 18 20 20 21 21 18 21
Ridge wind dir..NW NW NW NW W W NW NW NW NW
Ridge wind spd..15 20 20 20 20 20 20 20 20 20
Mix hgt (kft)...1.0 1.0 1.5 1.5 2.0 2.0 2.0 2.0 1.5 1.0
Transp wind dir.NW NW NW NW NW NW NW NW NW NW
Transp wind spd.17 18 21 21 22 25 25 24 23 20
SDspl kt-ft/100015 21 33 35 39 54 56 46 38 23
.THURSDAY NIGHT...
Sky/weather.........Mostly cloudy (70-80 percent).
CWR.................0 percent.
Chance of pcpn......10 percent.
Min temperature.....Around 10.
Max humidity........85-90 percent.
Wind (20 ft)........Northwest winds around 10 mph with gusts to
around 25 mph until 2300, then gusts around 20 mph.
Ridgetop wind.......Northwest 15 to 20 mph.
Mixing height.......500 ft AGL.
Transport winds.....Northwest 15 to 20 mph.
Smoke dispersal.....Poor.
TIME (MST) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........70 75 75 85 80 75 75 70 70 70 65 65
Weather cov.....
Weather type....
Tstm cov........
CWR.............0 0 0 0 0 0 0 0 0 0 0 0
Chc of pcpn (%).10 10 10 10 10 10 10 10 10 10 10 10
Temp............16 15 15 15 15 15 15 14 13 13 12 12
RH..............79 81 82 82 82 83 83 84 85 87 87 88
20 FT wind dir..NW NW NW NW W W W W W W NW NW
20 FT wind spd..11 11 11 11 11 11 11 10 10 10 9 9
20 FT wind gust.21 21 20 19 19 18 18 17 16 14 14 14
Ridge wind dir..NW NW NW NW W W W W W W NW NW
Ridge wind spd..20 20 20 20 20 20 20 15 15 15 15 15
Mix hgt (kft)...1.0 1.0 1.0 1.0 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
Transp wind dir.NW NW NW NW NW NW NW NW NW NW NW NW
Transp wind spd.20 20 18 18 18 18 18 18 18 17 17 16
SDspl kt-ft/100025 19 17 16 16 16 16 17 17 16 15 14
.FRIDAY...
Sky/weather.........Mostly cloudy (65-80 percent). Chance of snow
showers late in the morning. Snow showers late
in the afternoon.
CWR.................0 percent increasing to 75 percent late in the
afternoon.
Chance of pcpn......70 percent.
Max temperature.....Around 25.
Min humidity........70 percent.
Wind (20 ft)........West winds 10 to 14 mph with gusts to around 25
mph, especially after 1200.
Ridgetop wind.......West 15 to 20 mph.
Mixing height.......2000 ft AGL.
Transport winds.....Northwest 17 to 22 mph.
Smoke dispersal.....Poor.
TIME (MST) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........65 65 60 60 60 60 65 70 75 75 80 80
Weather cov..... CHC CHC CHC CHC CHC CHC DEF
Weather type.... SW SW SW SW SW SW SW
Tstm cov........
CWR.............0 0 0 0 0 0 0 0 0 0 0 80
Chc of pcpn (%).10 10 10 10 10 30 30 30 30 30 30 70
Temp............12 13 14 17 20 22 24 25 25 24 24 23
RH..............87 85 83 80 76 74 74 74 76 78 81 84
20 FT wind dir..NW W W W W W W W W W W W
20 FT wind spd..9 9 9 9 10 10 10 11 11 11 10 10
20 FT wind gust.14 14 16 17 18 18 19 20 21 21 20 19
Ridge wind dir..NW W W W W W W W W W W W
Ridge wind spd..15 15 15 15 15 15 15 20 20 20 15 15
Mix hgt (kft)...1.0 1.0 1.0 1.0 1.5 2.0 2.0 2.0 1.5 1.5 1.5 1.0
Transp wind dir.NW NW NW NW NW NW NW W W W W W
Transp wind spd.17 17 18 20 21 22 22 22 22 20 17 17
SDspl kt-ft/100015 16 17 24 31 38 38 36 35 28 23 20
.FORECAST DAYS 3 THROUGH 5...
.SATURDAY...
Mostly cloudy. Snow showers. Lows around 15. Highs in the mid
20s. West-northwest winds around 12 mph with gusts 25 to 30 mph.
.SUNDAY...
Partly cloudy. Slight chance of snow showers. Lows around 10.
Highs in the mid 20s. Northwest winds around 10 mph with gusts
around 20 mph.
.MONDAY...
Mostly cloudy. Slight chance of snow showers. Lows around 15.
Highs around 30. West winds around 11 mph with gusts 20 to 25 mph.
$$
Forecaster...Wittmann
Requested by...Theresa Froseth
Type of request...PRESCRIBED
.TAG 2526906.0/RIW
.DELDT 12/03/25
.FormatterVersion 2.0.0
.EMAIL Theresa.Froseth@usda.gov